The invention departs from an apparatus for collecting tissue samples by excising a segment from tissue, and a corresponding method for harvesting of tissue samples described in WO 99/44505 which is incorporated by reference into this specification. The biopsy apparatus of WO 99/44505 comprises a biopsy instrument and a holder.
In this specification, the terms “proximal” and “distal” refer to the person extracting a biopsy sample; the terms “front” and “rear” have a corresponding meaning. Thus, the proximal end of a biopsy apparatus is its rear end, pointing away from the patient.
The biopsy instrument of WO 99/44505 comprises a canula with a distal open cutting end and a through opening in its wall near the distal end, a finger tube slidingly disposed on the canula and provided with a finger at its distal end, and a stylet slidingly disposed in the canula, the finger being insertable into the opening in the canula wall and axially displaceable in a forward direction so as to be deflected towards the axis of the canula.
The holder of WO 99/44505 comprises a housing, means for releasably coupling the biopsy instrument to the housing; and compressed coil means for consecutive axial displacement of the canula and the tube in combination in a distal direction, and then of the tube in respect of the canula in the same direction. To expel a harvested biopsy sample from the canula, the holder further comprises means for consecutive displacement of the tube, and of the tube and the canula in combination, in a proximal direction. At their respective distal ends of the canula, the tube and the stylet are provided with end sections for mounting in the holder.
WO 99/44504 also discloses a loading assembly for the holder. The loading assembly comprises a loading arm swivellingly attached at its one end to the housing, an intermediate arm swivellingly attached at its one end to the loading arm and at its other end to a catch holding the canula end section during tensioning and in a tensioned position in respect of a tension spring or during compression or in a compressed position in respect of a compressing spring (the latter being preferred), the catch being displaceable in a proximal direction against the resistance of the spring and being adapted to be held there for intentional release.
A biopsy apparatus comprising the holder and the loading assembly of WO 99/44504 can be manufactured for single use in which case it is supplied to the customer preferably with the biopsy instrument of WO 99/44505 already mounted. It can, however, also be designed for repeated use with disposable sets of the biopsy instrument.
The aforementioned biopsy apparatus intended for single use, that is, provided to the user with the biopsy instrument already mounted, does not require other manual skills than performing its proper medical operation, that is, taking a biopsy sample from a patient and expelling the sample from the canula thereafter.
This is not so with the multiple-use biopsy apparatus in which a new biopsy instrument has to be mounted for each biopsy. Since the biopsy apparatus comprises three parts which are slidingly displaceable in regard to each other, their mounting, in a given spatial relationship, requires skillful handling. To this adds the sharp tip of the stylet and the front edge of the canula which may cause wounds if not properly handled in mounting or which may be accidentally damaged, as may be the tiny tissue excision means, that is the finger of the finger tube. Thus there is ample room for improvement in respect of making the loading process a routine measure, including modification of the biopsy apparatus and the loading assembly.